Fuel tank control for tractor trailors

Abstract

A fuel tank control for controlling excess fuel in a motor vehicle having at least two fuel tanks. A first fuel tank and a second fuel tank are connected to a motor whereby fuel is supplied to the motor from one fuel tank at a time. A first fuel supply line is connected to an outlet of the first fuel tank and a second fuel supply line connected to an outlet of the second fuel tank to supply fuel to the motor. A switch controls which fuel tank is used. A fuel return line is connected to the motor to receive excess fuel. The fuel return line is connected to a valve having an internal spool to regulate which tank the fuel is to be returned. In operation, when the first fuel pump is operated, the spool is adjusted to return the excess fuel to the first fuel tank via a first outlet line and when the second fuel pump is operated, the spool is adjusted to return the excess fuel to the second fuel tank through a second outlet line. The spool is adjusted by the pressure created by the fuel in the fuel supply line.

What is claimed is:  
     
       1. A fuel tank control for controlling excess fuel to an engine of a vehicle, said vehicle having at least two fuel tanks, comprising: 
       a first fuel tank having a first fuel pump and a second fuel tank having a second fuel pump;  
       a first fuel supply line connected to an outlet of the first fuel pump, a second fuel supply line connected to an outlet of the second fuel pump, each of the first fuel supply line and second fuel supply line being connected to supply pressurized fuel to an injection system of the vehicle engine and fuel pressure to a control valve;  
       a switch to control which fuel pump is operated; and  
       a fuel return line connected to the motor to receive excess fuel, said fuel return line being connected to the valve, said valve having an internal spool including at least one passage to regulate which tank the fuel is to be returned;  
       wherein when the first fuel pump is operated, the spool is translated to position a passage to return the excess fuel to the first fuel tank via a first outlet line and when the second fuel pump is operated, the spool is translated to position a passage to return the excess fuel to the second fuel tank through a second outlet line.  
     
     
       2. The fuel tank control of  claim 1  wherein the fuel return line is split into a first line and a second line, the first and second lines being connected to the valve through a first inlet hole and a second inlet hole, respectively; the valve having first and second outlet holes aligned with said first and second inlet holes, respectively; 
       wherein the first outlet line is in communication to the first outlet hole when a passage is positioned between said first inlet and outlet holes and the second outlet line is in communication to the second outlet hole when a passage is positioned between said second inlet and outlet holes,  
       whereby the valve operates such that fuel returning to the tanks flows either through the first inlet hole, through the spool passage, and out the first outlet hole or through the second inlet hole, through the spool passage, and out the second outlet hole.  
     
     
       3. The fuel tank control of  claim 2  wherein the valve has first and second ends and wherein the first fuel supply means is connected to the first end of the valve and the second fuel supply means is connected to the second end of the valve, 
       wherein when the first fuel pump is operated, the following fuel pressures forces the spool in the valve away from the first fuel supply line in order to allow a passage in said spool to align with said first inlet and outlet holes and excess fuel to flow into the first fuel tank, and  
       wherein when the second fuel pump is operated, the flowing fuel pressure forces the spool in the valve away from the second fuel supply line in order to allow a passage in said spool to align with said second inlet and outlet holes in order to allow excess fuel to flow into the second fuel tank.  
     
     
       4. The control system of  claim 1  wherein the at least one passage is at least one groove or hole. 
     
     
       5. The control system of  claim 1  wherein the spool includes two grooves, a first groove being alignable with said first inlet and outlet holes of said valve, the second groove being alignable with said second inlet and outlet holes of said valve. 
     
     
       6. The control system of  claim 1  wherein the spool includes two holes, a first hole being alignable with said first inlet and outlet holes of said valve, the second hole being alignable with said second inlet and outlet holes of said valve.